1. Field of the Invention
The present invention relates to hydronic floor, wall and ceiling heating systems for heating an enclosed space by circulating a heating fluid through a tubing system and more particularly to an improved heat tubing receptacle or channel and novel cooperation with surrounding thermally conductive surfaces.
2. Description of the Prior Art
In general, hydronic radiant heating systems are well known in the prior art and typically include means for circulating heating fluid, usually hot water, through a system of flexible heating pipes or tubes embed in either the floor, wall or ceiling of the room to be heated. These systems usually include some form of heating tube holder and a heat transfer medium, in the form of heating plates or fins to spread the heat from the tubing and receptacle to a surrounding thermally conductive area. Several methods for supporting the heating tubes and enhancing heat transfer are available, including extruded tube receptacles constructed from thermally conductive materials such as copper or aluminum with integral wings or plates for transferring heat to the surrounding area. Other systems rely on channels formed in sheet metal with planar wings or the like for spreading the heat. Still others rely on a combination of extruded cross sections and sheet metal components to make up the heat distribution panel. The McCall U.S. Pat. No. 4,624,242 and the Reed U.S. Pat. No. 5,477,848 are examples of the latter type of construction wherein extruded cross sections are utilized in combination with sheet metal components to make up the heat distribution panel. Examples of the use of extruded cross sections for both mounting the heat tubing and providing integral heat transfer plates located in different positions on the tube retaining channel are the Billota et al U.S. Pat. No. 5,743,330 and the Fitzemeyer U.S. Pat. No. 6,283,382, both of which utilize a retention channel with a semicircular cylindrical inside surface for holding a round heating tube. Applicant's own prior U.S. Pat. No. 5,454,428 is directed to a heat distribution panel and system wherein an extruded module includes integral side fins or heat transfer plates with an elongated tubing receptacle. According to my prior patent, the tubing receptacle includes an elongated tube-receiving space having an inner wall with a circumference extending through an arc greater than 180° with guide ways extending outwardly divergent therefrom for initially guiding the tubing into the tube receiving space. With the use of plastic deformable tubing having an outside diameter nominally the same as the diameter of the tube receiving space, the tubing is easily snapped into the channel with full surface contact between the wall of the tubing and the inner walls of the receptacle. Full surface contact thus eliminates air gaps so as to provide for optimum heat transfer between the tubing and the receptacle walls essentially by conduction. Surface contact between the tubing and receptacle walls may even be enhanced by the internal pressure in the tubing created when heating fluid is circulated. Because the tube receiving wall of the receptacle closely matches the circular shape and diameter of the tubing, once the tubing is in place, it will strongly grip the tubing without the need for glues, adhesives, sealants, filler material or other fasteners.
The Canadian Patent No. 2,078,185 to Joachim Fiedrich is illustrative of still another method of supporting the hot water tubing. In this patent, the tubing is confined in slots formed between wood sleeper panels, see FIG. 6, with a compliant caulking or epoxy adhering the tubing within the channel between the wood sleeper panels and in tangential contact with an overlying radiant plate.
The prior art heat distribution panels or modules, including the tube holding extrusions and heat transfer plates, are configured so as to engage the heating tubes only in the linear runs. Thus, when the heating system is assembled with the continuous heating tube lay-out in a generally serpentine pattern, no provision is made for tube retention or heat transfer enhancement along the curved sections of the heating tube which may even be left exposed if installation is made beneath existing floors. Alternatively the tubes may be contained in grooves in wooden sleeper panels at the ends of parallel straight runs of the tubing. In recent years, plastic tubing such as polyethylene or polybutylene has come into wide use for hot water circulation in radiant heating systems in nearly all types of building structures. A demand has thus arisen for not only less expensive radiant heat distribution panel systems but also for more efficient heat transfer methods, especially in private home construction.